Michael Quinion's World Wide Words newsletter of the 23rd February directed me to this article (Observer Magazine, 3 Feb 2008, p.9), and to the word sleevefacing: the practice of obscuring one's face (or other body parts) in one's Facebook profile picture by holding up a record sleeve, especially one similar enough to its surroundings to cause a visual illusion.
It's a lovely example of a coinage that will probably never get past its very restricted context of use, and of a word playing catch-up with the phenomenon it describes. 'Sleevefacing' is an unusual creation, probably simply from sleeve + face (n.) + ing, since it would require a new sense of 'face' (v.) meaning something like 'to have (something) as one's face; to make a surface covering of (something)'*, which itself would barely be applicable outside this context.
Anyway, a picture is worth a thousand irregular neologisms in this case, so: http://www.sleeveface.com.
* Cf. OED face v. 13.
# Alex Steer (06/03/2008)